As alternatives to conventional lighting apparatuses such as incandescent lamps and fluorescent lamps, planar light-emitting panels such as organic EL light-emitting panels have been focused on in recent years and investigated by many researchers.
This planar light-emitting panel incorporates a thin, planar light-emitting tile. Examples of the planar light-emitting panel include an organic EL light-emitting panel where an organic EL tile is surrounded by a jacket (frame).
This organic EL tile forms an organic EL element including opposing thin film electrodes, either or both of which has(have) a translucent property, and a thin film organic light-emitting layer laminated between the electrodes, on a base glass substrate or a substrate such as a translucent resin film/a metallic sheet. The formed organic EL element is then sealed with a predetermined sealing method.
When electric power is supplied between the opposing electrodes between which the thin film organic light-emitting layer is interposed, electrons and holes recombine in the thin film organic light-emitting layer, thus the planar organic EL tile emits light due to this recombination. So to speak, this organic EL tile can be referred to as a planar light-emitting tile. That is, the organic EL tile is a superior, thinner, lighter, planar light-emitting device.
To use a planar light-emitting tile as a lighting apparatus, a substrate of the planar light-emitting tile must be free from cracking and chipping. To use a planar light-emitting tile as a lighting apparatus, edges of the planar light-emitting tile must be treated so as to prevent injuries such as a scratch on a finger. Therefore, in order to use a planar light-emitting tile as a lighting apparatus, a casing such as a jacket satisfying the above described requirements is required, in addition to a structure for protecting side faces of a substrate. When using a planar light-emitting tile as a lighting apparatus, a casing should be improved to utilize the advantages of a thinner, lighter, and planar light-emitting tile as much as possible.
Patent Documents 1 to 4, for example, disclose casing structures of conventional planar light-emitting tiles.